Survival Outcomes in Patients Undergoing Pelvic Exenteration for Pelvic Mucosal Melanomas: Retrospective Single Institution Australian Study.

Background: Pelvic mucosal melanomas, including anorectal and urogenital melanomas, are rare and aggressive, with a median overall survival of up to 20 months. Pelvic mucosal melanomas behave differently from their cutaneous counterparts and present late with locoregional disease, making pelvic exenteration its only curative surgical option.

Objective: This study aimed to evaluate the survival outcomes after pelvic exenteration in pelvic mucosal melanomas at Royal Prince Alfred Hospital.

Design: Retrospective case series from a prospectively collected pelvic exenteration database from October 1994 to November 2023.

Setting: Royal Prince Alfred Hospital (quaternary institution), Camperdown, New South Wales, Australia.

Patients: Seven patients undergoing pelvic exenteration for pelvic mucosal melanoma.

Main outcome measures: Overall survival, disease-free survival, and complication rates.

Results: Of the 7 patients, most were women (n = 5; 71.4%) and had a median age of 65 years (range, 36-79). Five patients (71.4%) underwent pelvic exenteration for primary pelvic mucosal melanoma, 3 of which were anorectal and 2 vaginal melanomas. Two patients (28.6%) had recurrent anorectal melanoma and received neoadjuvant radiotherapy after an initial wide local excision. Three patients (42.9%) required total pelvic exenteration, whereas 2 required a central pelvic exenteration (28.6%). The remaining procedures included central and lateral pelvic exenteration and anterior, central, and lateral pelvic exenteration. The median length of hospital stay was 19.7 days. Five patients had postoperative complications with 1 major complication (Clavien-Dindo grade IIIa). At the completion of the study, there were 4 mortalities. Mean survival was 23.6 months (range, 2-100) with a recurrence rate of 83%. The median time to recurrence was 3 months, despite 6 patients (85.7%) having R0 resections. Distant recurrence, specifically to bone, the lungs, and the liver, was most common.

Limitations: Small study cohort due to rarity of disease, limiting generalizability.

Conclusions: Pelvic exenteration for pelvic mucosal melanoma appears to help control local disease as recurrence is most commonly distant or regional. See Video Abstract.